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| # .NET Standard vNext | ||
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| This document describes the plan for .NET Standard *vNext*, which includes the | ||
| definition of its API surface. | ||
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| ## Goals | ||
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| * **Include `Span<T>`**. In .NET Core 2.1 we've added `Span<T>` which is an | ||
| array like type that allows representing managed and unmanaged memory in a | ||
| uniform way and supports cheap slicing. It's at the heart of most | ||
| performance-related improvements in .NET Core 2.1 and allows managing buffers | ||
| in a more efficient way as it helps in reducing allocations and copying. | ||
| `Span<T>` is considered a core type and requires runtime and compiler support | ||
| in order to be fully leveraged. Please note that when we refer to `Span<T>` in | ||
| this document, we really mean the family of span-related features which | ||
| includes other types such as `ReadOnlySpan<T>`, `Memory<T>`, | ||
| `ReadOnlyMemory<T>`, and the new `System.Buffers` namespace. | ||
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| * **Include core-APIs working with spans**. While `Span<T>` is available as a | ||
| .NET Standard compatible NuGet package (`System.Memory`) adding this package | ||
| cannot extend the members of .NET Standard types that deal with spans. For | ||
| example, .NET Core 2.1 added many APIs that allow working with spans, such as | ||
| `Stream.Read(Span<Byte>)`. Part of the value proposition to add span to .NET | ||
| Standard is to add the companion APIs as those cannot be added using a NuGet | ||
| package. | ||
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| * **General Goodness**. Since .NET Core was open sourced, we've added many small | ||
| features across the base class libraries such as `System.HashCode` for | ||
| combining hash codes or new overloads on `System.String`. There are about ~800 | ||
| new members in .NET Core that are on types that are already in .NET Standard | ||
| 2.0. | ||
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| ## Decisions | ||
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| We did a diff between .NET Core 2.1 and .NET Standard 2.0 to see which APIs that | ||
| were added in .NET Core would be great candidates for inclusion in the standard. | ||
| From that list we made the following decisions: | ||
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| * **Include** Brotli as `HttpClient` depends on it | ||
| * **Not include** `Microsoft.CSharp` (the standard is language neutral) | ||
| * **Not include** `Microsoft.VisualBasic` (the standard is language neutral) | ||
| * **Not include** `DataAnnotations` (out-of-band today) | ||
| * **Not include** `DiagnosticSource` (out-of-band today) | ||
| * **Not include** `System.Collections.Immutable` (out-of-band today) | ||
| * **Not include** `System.Reflection.Metadata` (out-of-band today) | ||
| * **Not include** `System.Runtime.InteropServices.WindowsRuntime` (out-of-band | ||
| today) | ||
| * **Not include** `System.Runtime.Loader` (currently a .NET Core only concept | ||
| and not ready for standardization) | ||
| * **Not include** `RegexCompilationInfo` as it throws on .NET Core & Xamarin and | ||
| we don't plan on implementing the API ever. | ||
| * **Not include** `System.Threading.Tasks.Dataflow` (out-of-band today) | ||
| * **Not include** `IApplicationResourceStreamResolver` (was plumbing for | ||
| Silverlight convergence. It's obsoleted.) | ||
| * **Not include** `System.Xml.Serialization.SchemaImporter` (doesn't seem | ||
| useful) | ||
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| ***Note**: I haven't diffed Mono/Unity as my understanding is that neither | ||
| platform added any APIs at the base layer that would be good candidates for | ||
| inclusion.* | ||
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| ## Open issues | ||
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| * **Version number**. In contrast to .NET Standard 2.0, which was a massive | ||
| update in terms of APIs and the .NET Framework compatibility mode, this update | ||
| seems relatively incremental. Also, the payload is comparable to .NET Core | ||
| 2.1, hence .NET Standard 2.1 seems to make the most sense. | ||
| - .NET Core and .NET Standard aren't the same thing. People will expect that | ||
| the next version is `3.0` as that's what we called .NET Core. However, the | ||
| API set is closer to `2.1` and argubly makes more sense within the context | ||
| of the standard. | ||
|
There was a problem hiding this comment. What would the plans be for incorporating .NET Core 3 API enhancements? Would that be .NET Standard vNext++?
Author
There was a problem hiding this comment.
We want to avoid defining the standard with APIs that are in-flux as this violates our inclusion principles.
Correct There was a problem hiding this comment. Wouldn't it be ill-advised to remove a lot of existing functionality and call it an incremental version? While I'm all for the removal of things like data annotations out of standard, calling it an incremental change while containing application breaking features seems wrong to me
Author
There was a problem hiding this comment. Sorry, I see the confusion. I'll update the document. Exclusion here means "excluded from the set of candidates". These were never part of .NET Standard. |
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| - We could make it date-based | ||
| - Or we could go with levels (10-16, 20, etc.) | ||
| * **Some features require runtime work**. We need to make sure implementers are | ||
| aware what adding these means to their runtime: | ||
| - `Span<T>` | ||
| - `Vector<T>` | ||
| - `DispatchProxy` | ||
| - `RefEmit` | ||
| - For the full list, see issues labelled as [runtime-impact]. | ||
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| ## API suggestions | ||
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| All API suggestions are labelled as [netstandard-api]. API suggestions that | ||
| might require runtime changes are labelled [runtime-impact]. | ||
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| [netstandard-api]: https://github.com/dotnet/standard/labels/netstandard-api | ||
| [runtime-impact]: https://github.com/dotnet/standard/labels/runtime-impact | ||
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| ### Major features | ||
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| * [Add reflection emit](https://github.com/dotnet/standard/pull/829) | ||
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There was a problem hiding this comment. I have concerns about this from the Unity side, as mentioned in my comment on the specific PR.
Author
There was a problem hiding this comment. Let's discuss the details in the actual PR. I'll clarify how I envision we review this. |
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| * [Add Brotli compression](https://github.com/dotnet/standard/pull/822) | ||
| * [Add SIMD-accelerated vector types](https://github.com/dotnet/standard/pull/821) | ||
| * [Add System.IO.Enumeration](https://github.com/dotnet/standard/pull/820) | ||
| * [Add Span<T> and related APIs](https://github.com/dotnet/standard/pull/819) | ||
| * [Add runtime API to get ECMA335 metadata](https://github.com/dotnet/standard/pull/805) | ||
| * [Add RuntimeFeature](https://github.com/dotnet/standard/pull/804) | ||
| * [Add converters for drawing primitives and known colors](https://github.com/dotnet/standard/pull/803) | ||
| * [Add DbProviderFactories](https://github.com/dotnet/standard/pull/802) | ||
| * [Add ITuple](https://github.com/dotnet/standard/pull/800) | ||
| * [Make TypeInfo extensible](https://github.com/dotnet/standard/pull/831) | ||
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| ### Miscellaneous improvements | ||
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| The long tail of various small improvements have been broken down into PRs for | ||
| each of the namespaces: | ||
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| * [Microsoft.Win32.SafeHandles](https://github.com/dotnet/standard/pull/806) | ||
| * [System](https://github.com/dotnet/standard/pull/823) | ||
| * [System.Collections.*](https://github.com/dotnet/standard/pull/807) | ||
| * [System.ComponentModel](https://github.com/dotnet/standard/pull/808) | ||
| * [System.Data.*](https://github.com/dotnet/standard/pull/809) | ||
| * [System.Diagnostics.*](https://github.com/dotnet/standard/pull/810) | ||
| * [System.Drawing](https://github.com/dotnet/standard/pull/825) | ||
| * [System.Globalization.*](https://github.com/dotnet/standard/pull/811) | ||
| * [System.IO.*](https://github.com/dotnet/standard/pull/826) | ||
| * [System.Linq.*](https://github.com/dotnet/standard/pull/812) | ||
| * [System.Net.*](https://github.com/dotnet/standard/pull/827) | ||
| * [System.Numerics](https://github.com/dotnet/standard/pull/813) | ||
| * [System.Reflection](https://github.com/dotnet/standard/pull/828) | ||
| * [System.Resources](https://github.com/dotnet/standard/pull/814) | ||
| * [System.Runtime.* ](https://github.com/dotnet/standard/pull/815) | ||
| * [System.Security.* ](https://github.com/dotnet/standard/pull/824) | ||
| * [System.Text.*](https://github.com/dotnet/standard/pull/816) | ||
| * [System.Threading.* ](https://github.com/dotnet/standard/pull/817) | ||
| * [System.Xml.*](https://github.com/dotnet/standard/pull/818) | ||
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What is the plan for
xsd.exe? I've tried to generate XML schemas from netcore assemblies, and it failed. Same assembly compiled for NET472 -- works.